Pocket BotanistPlant guide
Tomato.
Solanum lycopersicum
Pronounced soh-LAH-num ly-koh-PER-sih-kum
Also known as Garden Tomato, Tomato
Tomatoes are popular, warm-season annuals grown for their delicious fruit. They come in a huge variety of shapes, sizes, and colors, making them a versatile addition to any garden. Proper support and consistent care are key to a bountiful harvest.
At a glance
- Care level
- Moderate
- Plant type
- Annual vegetable
- Light
- Full sun
- Indoor light
- direct
- Water
- Every 1 to 3 days
- Mature size
- 1 to 3 meters tall
- Growth rate
- fast
- Hardiness
- USDA 2 to 11
- Bloom time
- Summer
Care
Tomatoes need plenty of sun and consistent watering to prevent issues like blossom end rot. Support the plants with stakes or cages as they grow to keep the fruit off the ground and improve air circulation. Watch out for common pests like aphids and hornworms.
- Watering
- Water deeply and consistently, especially during fruit development. Avoid overhead watering to reduce disease risk.
- Feeding
- Feed regularly with a balanced fertilizer, switching to one lower in nitrogen and higher in phosphorus once flowering begins.
- Pruning
- Prune suckers (side shoots) on indeterminate varieties to improve fruit production and air circulation. Remove lower leaves touching the soil.
- Repotting
- Tomatoes are typically grown as annuals and not repotted, but seedlings can be transplanted into larger pots if started indoors.
- Soil
- Rich, well-draining loam
- Soil pH
- 6.0 to 6.8
- Temperature
- 15 to 30°C
- Humidity
- 50 to 70%
- Drought tolerance
- moderate
- Lifespan
- Annual
- Deer and rabbits
- low
Signs it needs repotting
- Roots circling densely around the bottom of the pot.
- Water drains through the pot very quickly without soaking the soil.
- Plant growth appears stunted despite adequate light and water.
- White, web-like roots are visible on the soil surface.
Safety
- People
- The leaves, stems, and unripe fruit contain solanine, which can cause stomach upset and other symptoms if ingested in large quantities.
- Pets
- The fruit is safe for pets, but the leaves and stems contain solanine and can be toxic if ingested in large quantities.
- Children
- Small children might be tempted to eat unripe tomatoes, which can cause gastrointestinal upset due to solanine content.
- Contact allergens
- Some individuals may experience skin irritation from handling tomato plants, especially the leaves and stems.
- Airborne allergens
- Tomato pollen can be an allergen for sensitive individuals, potentially causing respiratory issues.
- Edibility
- While the ripe fruit is edible, unripe or green parts of the plant can be toxic.
How to identify it
- Fuzzy stems and leaves
- Yellow, star-shaped flowers
- Vining or bushy growth habit
- Fleshy, edible berries (fruit)
- Distinctive, pungent aroma
- Height
- 0.3 to 3m
- Spread
- 0.3 to 1m
- Leaves
- green, evergreen
- Flowers
- yellow, 1 to 2cm
- Fruit
- red, yellow, orange, green, purple, pink, Summer to Fall
Common problems
- Early Blight — Causes dark spots with concentric rings on leaves, leading to yellowing and leaf drop.
- Late Blight — A fast-spreading disease causing water-soaked lesions on leaves and stems, often leading to plant death.
- Tomato Hornworm — Large green caterpillars that can defoliate plants rapidly.
- Aphids — Small, sap-sucking insects that can weaken plants and transmit diseases.
- Blossom End Rot — A dark, sunken spot on the blossom end of the fruit, usually caused by inconsistent watering and calcium deficiency.
Growing it
- Propagation
- seed, cuttings
- When to plant
- Spring, Summer
- Overwintering
- Tomatoes are annuals and will not survive freezing temperatures. In cooler climates, they are grown as annuals. In frost-free regions, they might perennialize if protected, but yield often declines significantly in subsequent years.
- In containers
- Excellent for containers, especially determinate or dwarf varieties. Use pots at least 5-gallon size per plant, with good drainage.
Seed Starting Indoors
- Sow seeds about 1/4 inch deep in seed starting mix 6-8 weeks before the last expected frost.
- Keep soil consistently moist and warm (70-80°F or 21-27°C) for germination.
- Provide ample light once seedlings emerge, using grow lights if necessary.
- Harden off seedlings by gradually exposing them to outdoor conditions for a week before transplanting.
- Transplant into the garden after all danger of frost has passed and soil has warmed.
Stem Cuttings
- Take 4-6 inch cuttings from healthy, non-flowering side shoots.
- Remove the lower leaves, leaving only the top few.
- Dip the cut end in rooting hormone (optional).
- Place the cutting in moist potting mix or a glass of water.
- Keep warm and in bright, indirect light until roots form, then transplant.
Plant tomatoes with herbs like basil and chives to enhance flavor and deter pests, and consider root vegetables like carrots that improve soil structure.
Grows well with
- Basil — Basil is thought to improve tomato flavor and repel some pests like tomato hornworms and whiteflies.
- Marigolds — Certain varieties of marigolds can deter nematodes in the soil, which can harm tomato roots.
- Carrots — Carrots help loosen the soil, which can benefit tomato root growth, and they don't compete for the same nutrients.
- Onions — Onions can help deter pests that might attack tomatoes, and they have different nutrient needs.
Keep away from
Similar species
- Eggplant — Both are in the Solanum genus and share similar cultural needs and susceptibility to some pests and diseases.
- Peppers — Peppers are also warm-season fruiting plants with similar light and soil requirements.
- Potato — Potatoes are closely related to tomatoes within the Solanum genus and can be affected by some of the same diseases.
Science
- Family
- Solanaceae
- Genus
- Solanum
- Order
- Solanales
- Class
- Magnoliopsida
- Native range
- Southwestern South America, specifically the Andes region.
- Conservation
- Not of conservation concern.
In its native habitat, it grows in disturbed soils and along the edges of forests, often as a sprawling vine.
- Value to wildlife
- nectar source, larval host plant
- Pollinators
- bees, butterflies, moths
- Uses
- culinary, ornamental
Through the year
Ecological indicators
- Salinity
- 1/9
- Soil reaction
- 6.5/9
- Light
- 8/9
- Temperature
- 7/9
- Moisture
- 6/9
- Nutrients
- 7/9
Taxonomy resolved against GBIF.
Questions people ask
- How much sun do tomatoes need?
- Tomatoes thrive in full sun, needing at least 6 to 8 hours of direct sunlight daily.
- What is the best soil for tomatoes?
- They prefer well-draining, fertile soil rich in organic matter.
- How often should I water tomatoes?
- Water consistently, aiming for about 1 to 1.5 inches of water per week, more in hot weather.
- When should I fertilize tomatoes?
- Fertilize at planting and then every 3 to 4 weeks with a balanced fertilizer or one formulated for tomatoes.
- Can tomatoes be grown in containers?
- Yes, many varieties do well in containers, provided they are large enough and have good drainage.
Where the name comes from
The genus name 'Solanum' comes from the Latin word 'solamen', meaning 'quieting' or 'comforting', possibly referring to its narcotic properties. The species name 'lycopersicum' is derived from Greek words 'lykos' (wolf) and 'persikon' (peach), leading to the common name 'wolf peach'.
Good to know
- The word 'tomato' comes from the Aztec word 'tomatl'.
- There are thousands of tomato varieties grown worldwide.
- Tomatoes were once believed to be poisonous in Europe.
- The largest tomato ever grown weighed over 11 pounds.
Is your tomato looking unwell?
This page is a general guide. Pocket Botanist diagnoses problems from a photo of your actual plant, works out watering for your light and conditions, and reminds you when care is due.
This guide was generated with AI and checked against GBIF taxonomy. It is general information, not horticultural or veterinary advice. Read about how we build these guides.